Repeater for wired pipe

ABSTRACT

A wired drill pipe electronic device includes a housing having a threaded connection at each end configured to couple to a wired drill pipe having double shoulder threaded connections. A chassis is disposed inside the housing and is configured to define at least one sealed atmospheric chamber between the chassis and the housing. The chassis defines an internal passage therethrough. The device includes a stress coupling to enable transmission of at least one of axial and torque loading from both the inner and outer shoulder of adjacent wired drill pipe segments through the housing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 60/942,863, filed on Jun. 8, 2007 entitled “TELEMETRY SYSTEMREPEATER.”

BACKGROUND OF THE DISCLOSURE

The invention relates generally to the field of pipe used to conveyinstruments along wellbores drilled through the Earth's subsurface. Moreparticularly, the invention relates to structures for repeaters used in“wired” drill pipe systems.

Rotary drilling systems known in the art for drilling wellbores throughsubsurface Earth formations typically use threadedly coupled segments(“joints”) of pipe suspended at the Earth's surface by a drilling unitcalled a “rig.” The pipe is used, in association with certain types oftools such as drill collars and stabilizers to operate a drill bitdisposed at the longitudinal end of a “string” of such pipe jointscoupled end to end. As a wellbore is drilled, and it becomes necessaryto lengthen the string of pipe, additional joints of pipe are coupled tothe string by threading them onto the upper (Earth's surface) end of thestring of pipe. Removing the string of pipe from the wellbore, such asto replace a drill bit, requires uncoupling joints or “stands” (segmentsconsisting of two, three or four coupled joints) of the pipe string andlifting the string from the wellbore. Such coupling and uncouplingoperations are an ordinary and necessary part of drilling a wellboreusing a rig and such pipe strings (“drill strings”).

It is known in the art to include various types of measuring devicesnear the lower end of a drill string in order to measure certainphysical parameters of the wellbore and the surrounding Earth formationsduring the drilling of the wellbore. Such instruments are configured torecord signals corresponding to the measured parameters in data storagedevices associated with the measuring devices. The measuring and storingdevices require electrical power for their operation. Typically suchpower is provided by batteries and/or a turbine powered electricalgenerator associated with the measuring devices. The turbine may berotated by the flow of drilling fluid (“mud”) that is pumped through acentral passageway or conduit generally in the center of the pipes andtools making up the drill string. It is also known in the art tocommunicate certain signals representative of the measurements made bythe devices in the wellbore to the Earth's surface at or close to thetime of measurement by one or more forms of telemetry. One such form isextremely low frequency (“ELF”) electromagnetic telemetry. Another ismodulation of the flow of mud through the drill string to causedetectable pressure and/or flow rate variations at the Earth's surface.

The foregoing power and telemetry devices have well known limitations.There has been a longstanding need in the art of wellbore drilling toprovide electrical power and a relatively high bandwidth communicationchannel along a drill string from the bit to the Earth's surface.Various structures have been devised to provide insulated electricalconductors in association with drill pipe to provide such power andsignal channels for a drill string. Such structures are generally knownas “wired” drill pipe. The features of the structures that have beendeveloped for such insulated electrical conductor channels are relatedto the particular requirements for pipes used for drill strings, namely,that they must be made so as to cause as little change as possible inthe ordinary handling and operation of drill pipe. As will beappreciated by those skilled in the art, such handling includes repeatedthreaded coupling and uncoupling. Use of the pipe string during drillingwill result in application to the pipe string of torsional stress,bending stress, compressional and tensional stress, as well as extremeshock and vibration. Thus, a commercially acceptable wired drill pipemust be as far as practicable transparent to the drill operator and mustbe operable under the types of stresses applicable to ordinary(non-wired) drill string components.

One type of wired drill pipe is described in U.S. Patent ApplicationPublication No. 2006/0225926 filed by Madhavan et al. and assigned tothe assignee of the present invention. The wired drill pipe disclosed inthe '926 publication includes a conduit for retaining wires in the wallof or affixed to the wall of a joint of drill pipe, as well aselectromagnetic couplings for the wires proximate the longitudinal endsof the pipe joint. The electromagnetic couplings transfer power andsignal between adjacent joints of wired drill pipe.

Irrespective of the type of wired drill pipe system used, it isdesirable to include one or more signal conditioner and amplificationdevices called “repeaters” at selected positions along the pipe stringto assure adequate signal amplitude at the Earth's surface for thesignals transmitted from the devices at the lower end of the drillstring, and vice versa. A repeater used with wired drill pipe istypically disposed in a short-length segment (about 3 to 10 feet or 1 to3 meters) of drill pipe or drill collar. On example of a structure for arepeater is described in U.S. Pat. No. 7,193,526 issued to Hall et al.Design challenges for signal repeaters include that the internaldiameter of the device should be at least as large as the smallestinternal diameter of every other component of the drill string to avoidexcessive restriction on the flow of drilling fluid through the drillstring; that the bending stiffness and moment of inertia are similar tothat of other components of the drill string having similar outerdiameter; and that the threaded connections used are essentiallyidentical to those used in the remainder of the drill string to maintaintransparency to the drill operator.

A particular issue to be addressed with repeaters in a drill string isthe type of threaded connection used in typical wired drill pipe. Suchconnections are known as “double shoulder” connections, examples ofwhich are described in the Madhavan et al. publication referenced above.Typically, such double shoulder threaded connections when used withwired drill pipe include a groove or similar feature formed into theinternal shoulder of the threaded coupling for retaining thecommunication coupling. It is desirable for the repeater to have themechanical characteristics described above, and to be usable withtypical double shoulder threaded connections, to be able to transfersome of the loading applied by the inner shoulder of the adjacentthreaded connection.

There continues to be a need for improvements to structures forrepeaters for wired drill pipe to increase their reliability,serviceability and ease of handling during drilling operations.

SUMMARY OF THE INVENTION

A wired drill pipe electronic device according to one aspect of theinvention includes a housing having a threaded connection at each endconfigured to couple to a wired drill pipe having double shoulderthreaded connections. A chassis is disposed inside the housing and isconfigured to define at least one sealed atmospheric chamber between thechassis and the housing. The chassis defines an internal passagetherethrough. The device includes a stress coupling to enabletransmission of at least one of axial and torque loading from both theinner and outer shoulder of adjacent wired drill pipe segments throughthe housing.

Other aspects and advantages of the invention will be apparent from thefollowing description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example drilling system using wired drill pipe andsignal repeaters.

FIG. 2 shows an example of a double shoulder threaded connection used intypical drill string components.

FIG. 3 shows one example of a structure for a repeater.

FIG. 4 shows more detail of a removable second shoulder adjacent to anelectronic chassis from the example repeater shown in FIG. 3.

FIG. 5 shows an exploded view of the removable second shoulder assemblyshown in FIG. 4.

FIG. 6 shows an example interior wall configuration for a housing forthe repeater shown in FIG. 3.

FIG. 7 shows a portion of the assembly of FIG. 5 coupled to the interiorof the housing.

FIG. 8 shows an example sealed electrical and/or optical connectionbetween the chassis and the shoulder assembly.

FIG. 9 shows an example connection between one end of the electronicchassis and a pin end of the repeater.

FIG. 10 shows another example of a removable second shoulder assembly.

FIG. 11 shows a different example of a repeater structure having boxconnections at each end.

FIG. 12 shows the example of FIG. 11 in more detail.

FIG. 13 shows more detail of a removable shoulder assembly of therepeater of FIG. 12.

FIG. 14 shows an alignment key used to prevent relative rotation.

FIG. 15 shows an example of a radial electrical and/or opticalconnection.

DETAILED DESCRIPTION

An example wellbore instrumented drilling system having wired drillpipe, with which various implementations of a repeater according to theinvention may be used is shown schematically in FIG. 1. A drilling rig24 or similar lifting device suspends a conduit called a “drill string”20 within a wellbore 18 being drilled through subsurface rockformations, shown generally at 11. The drill string 20 may be assembledby threadedly coupling together end to end a number of segments (called“joints”) 22 of drill pipe. The drill string 20 may include a drill bit12 at its lower end. When the drill bit 12 is axially urged into therock formations 11 at the bottom of the wellbore 18 and when it isrotated by equipment (e.g., top drive 26) on the drilling rig 24, suchurging and rotation causes the bit 12 to axially extend (“deepen”) thewellbore 18. The lower end of the drill string 20 may include, at aselected position above and proximate to the drill bit 12, a hydraulicmotor (“mud motor”) 10 that may be used to provide supplementalrotational energy to the drill bit 12 or all the rotational energy tothe drill bit 12. Proximate its lower end, the drill string 20 may alsoinclude an MWD instrument 14 and an LWD instrument 16 of types wellknown in the art. At least part of the power to operate the MWDinstrument 14 and LWD instrument 16 may be obtained from the electricalconductors (not shown in FIG. 1) associated with the wired drill string20.

During drilling of the wellbore 18, a pump 32 lifts drilling fluid(“mud”) 30 from a tank 28 or pit and discharges the mud 30 underpressure through a standpipe 34 and flexible conduit 35 or hose, throughthe top drive 26 and into an interior passage (not shown separately inFIG. 1) inside the drill string 20. The mud 30 exits the drill string 20through courses or nozzles (not shown separately) in the drill bit 12,where it then cools and lubricates the drill bit 12 and lifts drillcuttings generated by the drill bit 12 to the Earth's surface. Someexamples of MWD instrument 14 or LWD instrument 16 may include atelemetry transmitter (not shown separately) that modulates the flow ofthe mud 30 through the drill string 20. Such modulation may causepressure variations in the mud 30 that may be detected at the Earth'ssurface by a pressure transducer 36 coupled at a selected positionbetween the outlet of the pump 32 and the top drive 26. Signals from thetransducer 36, which may be electrical and/or optical signals, forexample, may be conducted to a recording unit 38 for decoding andinterpretation using techniques well known in the art. The decodedsignals typically correspond to measurements made by one or more of thesensors (not shown) in the MWD instrument 14 and/or the LWD 16instrument. Signals from the MWD and/or LWD instruments may also becommunicated along the one or more electrical conductors (not shown inFIG. 1) associated with the drill string 20.

It will be appreciated by those skilled in the art that the top drive 26may be substituted in other examples by a swivel, kelly, kelly bushingand rotary table (none shown in FIG. 1) for rotating the drill string 20while providing a pressure sealed passage through the drill string 20for the mud 30. Accordingly, the invention is not limited in scope touse with top drive drilling systems.

In the example shown in FIG. 1, at selected positions along the drillstring a repeater 23 may be provided. Each repeater 23 may containcircuits to amplify and condition signals originating from one directionalong the conductors (not shown in FIG. 1) in the wired drill pipe andto transmit the amplified and conditioned signals in the otherdirection. By using such repeaters, it is possible to extend the lengthof the drill string 20 substantially while maintaining good signalcommunication in both directions.

As explained in the Background section herein, one type of “wired” drillpipe is described in U.S. Patent Application Publication No.2006/0225926 filed by Madhavan et al. and assigned to the assignee ofthe present invention. The wired drill pipe disclosed in the '926publication includes a conduit for retaining wires in the wall of oraffixed to the interior wall of each joint of drill pipe, as well aselectromagnetic couplings for the wires proximate the longitudinal endsof each pipe joint. The couplings between the segments of pipe used inthe wired drill pipe include an electromagnetic transducer disposed in agroove formed in a longitudinal end of each pipe segment. The pipesegments typically include a female (“box”) connector at onelongitudinal end, and a male (“pin”) connector at the other longitudinalend. The type of threaded connection used is known in the art as a“double shoulder connection.” The threads on the pin and the box aretapered, meaning that the external diameter of the threads changes alongthe length of the connection. The tip or “nose” of the pin includes asubstantially planar face or shoulder on the inner diameter of theconnection (“inner shoulder”) that mates with a corresponding planarface or shoulder in the internal end (“base”) of the box.Correspondingly, at the base of the pin a second shoulder is formed onthe outer diameter of the connection (“outer shoulder”) that mates witha corresponding shoulder at the end of the box on the adjacentconnector. A typical threaded connection used with wired drill pipe isshown in FIG. 2 at 200. The pin is shown at 202, and the tapered threadon the pin is shown at 203. The box is shown at 204, and its taperedthread is shown at 205. The inner shoulder at the pin end is shown at202B. The corresponding inner shoulder at the base of the box is shownat 204B. A groove is formed in each of the pin inner shoulder 202B andcorresponding box inner shoulder 204B to receive a communicationcoupling, such as an electromagnetic transducer (not shown). Therespective grooves in the pin shoulder 202B and the box shoulder 204Bare shown at 202C and 204C. The external or outer shoulder is shown onthe pin at 202A and on the box at 204A. The double shoulder connectionshown in FIG. 2 provides metal to metal sealing of one pipe segment tothe adjacent segments and efficiently transfers both torque and axialloading between each pipe segment and the adjacent pipe segments.Notwithstanding the grooves formed in the inner shoulders for thecommunication couplings, at least some load is transferred from eachpipe segment to the adjacent segments through the inner shoulder. Theinner shoulders can also provide additional metal to metal sealing toseal drilling fluid under pressure inside the internal bore 206. Thethreaded connection 200 defines an internal bore 206 for passage ofdrilling fluid therethrough. The threaded connection 200 is typicallydesigned such that a minimum internal diameter d_(min) within theconnection 200 is at least as large as the minimum internal diameter ofevery other portion of the drill string (20 in FIG. 1).

Generally, a wired drill pipe electronic device according to variousaspects of the invention includes a housing having a threaded connectionat each end configured to couple to a wired drill pipe having doubleshoulder threaded connections. A chassis is disposed inside the housingand is configured to define at least one sealed atmospheric chamberbetween the chassis and the housing. The chassis defines an internalpassage therethrough. The device includes a stress coupling to enabletransmission of at least one of axial and torque loading from both theinner and outer shoulders of adjacent wired drill pipe segments throughthe housing. The device may include a communication coupling disposedadjacent to a corresponding communication coupling in the inner shoulderof each adjacent pipe segment to provide signal communication to devicesdisposed in the at least one atmospheric chamber.

An example structure for a wired drill pipe electronic device such as arepeater is shown in FIG. 3 at 23. The structure shown in FIG. 3 isconfigured to couple in the drill string (20 in FIG. 1) between twosegments of wired drill pipe or drill collars each having a doubleshoulder connection and a groove for a communication device disposed inthe inner shoulder thereof, such as the pin and box shown in FIG. 2. Theelectronic device structure described herein will be referred to forconvenience as a “repeater” because that is one of the intended purposesfor the structure. However, the described structure may be used withother electronic devices disposed in sealed enclosures that are intendedto be used with wired drill pipe having double shoulder connections.Accordingly, the use of the term “repeater” is not intended to limit thetypes of electronic devices that may be included in the structure or tolimit the scope of the present invention. The repeater 23 may include ahousing 301 formed from steel, or high strength non magnetic alloy suchas stainless steel, monel or an alloy sold under the trademark INCONEL,which is a registered trademark of Huntington Alloys Corporation,Huntington, W. Va. The housing 301 may include a double shoulder malethreaded connector or pin 302 at one longitudinal end configuredsubstantially as explained above with reference to FIG. 2, including agroove 302C for receiving a communication coupling (not shown) for awired drill pipe system. The structure of the pin 302 will be furtherexplained with reference to FIG. 9. The structure for the groove andcommunication coupling may be, for example, substantially as describedin the Madhavan et al. publication referenced above. It will be apparentto those skilled in the art that the pin 302 will transmit stress fromthe housing 301 to an adjacent coupled pipe segment (not shown) throughboth the outer shoulder and the inner shoulder. It should also beunderstood that the pin 302 could be substituted by a double shoulderbox connection in alternative examples.

The other longitudinal end of the housing 301 may define a femaleconnector or box 304. The box 304 is configured to receive acorresponding pin (not shown) of an adjacent segment (not shown) ofwired drill pipe, and therefore includes tapered internal threadssimilar to those shown at 205 in FIG. 2. However, the box 304 does notterminate in an internal shoulder at the base thereof as does theconventional box shown in FIG. 2.

The internal bore of the housing 301 on the box end in the presentexample is enlarged beyond that of a similar diameter segment of doubleshoulder drill pipe or drill collar to receive an electronic chassis308. The chassis 308 may be generally cylindrical in configuration andcan define an internal bore 306A having diameter at least as large asthe smallest internal bore (e.g., at 206 in FIG. 2) of all the othercomponents of the wired drill pipe string (20 in FIG. 1). The outerdiameter of the chassis 308 is selected to fit within the internal boreof the housing 301 through the box 304. The internal bore of the housing301 may be enlarged to receive the chassis 308 from the box endapproximately to a longitudinal position of a connector assembly 310that makes sealed electrical and/or optical connection to a conductor(not shown) that extends from the connector assembly 310 into the groove302C in the internal shoulder of the pin 302. The exterior of thechassis 308 may be sealed against the interior wall of the housing 301at selected longitudinal positions to provide a sealed enclosure forelectronic and/or electro-optical components by forming one or morerecesses or pockets into the exterior wall of the chassis 308. Anexample sealing device for the chassis 308 will be explained below withreference to FIG. 8. The connector assembly 310 and a longitudinal stopshoulder to limit longitudinal movement of the chassis 308 inside thehousing 301 will be further explained with reference to FIG. 9.

The chassis 308 may be longitudinally retained within the housing 301by, for example, a jam nut 312 that threadedly engages the interior wallof the housing 301. Axial bias loading may be provided by including oneor more springs 314 between the jam nut 312 and the longitudinal end ofthe chassis 308.

In the present example, the function of a “stress coupling” referred toabove is performed by a removable inner shoulder assembly 305 isdisposed in the housing 301 between the box 304 and the jam nut 312. Thepurposes of the removable inner shoulder assembly 305 are to transmittorque and axial loading from the nose of the pin (e.g., as shown at202B in FIG. 2) in the adjacent pipe segment (not shown), to provide agroove to receive a communication coupling (not shown) to mate with thecorresponding communication coupling in the inner shoulder of adjacentpipe segment, to make electrical and/or optical connection to certaincomponents in the chassis 308, and to enable longitudinal removal of thechassis 308 from the housing 301 through the box end for servicing asrequired.

FIG. 4 shows the removable inner shoulder assembly 305 in more detail.The assembly 305 includes a carrier 323 having an inner shoulder with agroove therein for a communication coupling, shown generally at 304C,for mating to the inner shoulder of the adjacent pipe segment.Electrical and/or optical connection may be made between the groove 304Cand the chassis through suitable passages sealed using a bulkheadfeedthrough connector 316 on the chassis 308 and a boot type connector318 affixed thereto from the carrier 323. Longitudinal position of thecarrier 323 with respect to the chassis 308 may be selected by the useof suitable shims 320. The foregoing connectors may be disposed in aseparate connector carrier 319. The carrier 323 may communicate torqueand/or axial loading from the shoulder 304C to the housing a segmentedlocking device 326 to be explained further below.

FIG. 5 shows an exploded view of the removable inner shoulder assembly305. The carrier 323, which may be formed from steel or other highstrength alloy as explained above with reference to the housing 301,includes an inner shoulder 304B to mate with the corresponding innershoulder on the pin of the adjacent pipe segment (e.g., 202 in FIG. 2)The shoulder 304B may include the previously mentioned groove 304C forreceiving a wired drill pipe communication coupling (not shown). Thecarrier 323 may include splines 324 formed on a portion of the outerdiameter of the carrier 323 to transmit torque loads to other componentsof the removable inner shoulder assembly 305. Such other components mayinclude four circumferential locking elements (which when assembled formthe locking device 326 in FIG. 4), including two “side” locking elements326C, 326D which are identical, and “upper” 326A and “lower” 326Blocking elements. Reference to “upper”, “lower” and “side” with respectto the locking elements is made only for purposes of identification inthe accompanying drawings and has no relationship to the actual positionof the locking elements.

The two side elements 326C, 326D may have a longitudinally extendingkeyway (not shown) for receiving a key 322, which prevents rotation ofthe assembly 305 in the housing (301 in FIG. 3). The housing (301 inFIG. 3) has a mating keyway as will be explained below with reference toFIG. 6. The top 326A and bottom 326B elements may extend laterally intoa mating slot (not shown) formed in the interior surface of the housing(301 in FIG. 3) to further resist rotation. Multiple radial grooves 326Emay be formed in the exterior face of the side locking elements 326C,326D to transmit axial load from the mating pin connection (e.g., 202 inFIG. 2) to the housing (301 in FIG. 3). Each of the upper 326A and lower326B locking elements may include circumferential extensions 329A thatextend over corresponding circumferential recesses 329B in thelongitudinal ends of the side locking elements 326C, 326D.

To assemble the second shoulder assembly 305 into the housing (301 inFIG. 3), the side locking elements may be inserted into their respectiveretaining features (explained below with reference to FIG. 6) in theinterior of the housing (301 in FIG. 3) by extending them laterally intosuch features. The upper 326A and lower 326B locking elements may thenbe inserted longitudinally into the circumferential spaces left betweenthe circumferential ends of the side locking elements 326C, 326D. Theupper 326A and lower 326B locking elements may be coupled to the sideelements 326C, 326D through the extensions 329A using cap screws (notshown) or the like. The locking elements are thus longitudinally andlaterally retained within the housing (301 in FIG. 3). The carrier 323may then be inserted into the locking elements. To position the carrier323 longitudinally precisely, shims 320 may be inserted onto theexterior of the carrier 323.

FIG. 6 shows an example of features formed into the interior wall of thehousing 301 to retain the locking elements (FIG. 5) within the housing301. The features may include axially spaced apart, circumferentialgrooves 332 to mate with corresponding grooves (326E in FIG. 5) on theexterior of the locking elements. The grooves 332 cooperate with thegrooves (326E in FIG. 5) on the locking elements to transmit axialloading from the mating pin (202 in FIG. 2) to the housing 301. A keyway330 may also be formed longitudinally to receive the keys (322 in FIG.5) to assist in transmitting torque to the housing 301.

An oblique view of the assembled locking elements 326A, 326B, 326C,326D, keys 322 and carrier is shown in FIG. 7 to explain the respectivelocations of the foregoing when assembled.

There are two sets of shims 320 used in the assembly. Referring onceagain to FIG. 5, some of the shims are used for length adjustment andare built up to an exact thickness as needed to position the carrier 323inner shoulder face 304B at an exact distance relative to the boxconnection face. The other shims 320 can be used for connectoradjustment to position the connector carrier (319 in FIG. 4) at theproper location for mating the connectors (316, 318 in FIG. 4). Theconnector carrier (319 in FIG. 4) can be a separate piece that containstwo rubber booted connectors that mate with fluid-to-air connectors(bulkhead connectors) mounted in the end of the chassis (308 in FIG. 4).The connectors can be wired to the wired drill pipe communicationcoupling disposed in the groove 304C in the end of the carrier 323. Theshims 320 can also be used to adjust the inner shoulder assembly asneeded for shortening of the housing 301 due to occasional rethreading.

Referring to FIG. 8, the jam nut 312 may be a multi-segment jam nutassembled within the housing, and which may have overlapping surfacesthat bolt together with screws 312A to form a single assembly, in amanner similar to the locking elements explained with reference to FIG.5. The jam nut 312 is used to hold the chassis 308 securely in placeagainst a shoulder (350 in FIG. 9) in the housing 301. The jam nut 312can be tightened against a spring 314 which is compressed against thechassis 308 holding it in place against the shoulder (350 in FIG. 9).

There may be a T-shaped or other geometry locking groove 342 formed inthe exterior of the chassis 308 beneath an alignment pin 340. Thelocking groove 342 traps the alignment pin 340 to keep it from comingout of the groove 342. The groove 342 in the chassis 308 allows thealignment pin 340 to be inserted through a hole in the wall of thehousing 301 prior to entering the groove 342. The groove 342 andalignment pin 340 allow the chassis 308 to be moved longitudinallyagainst the shoulder (350 in FIG. 9) while maintaining rotationalalignment of the chassis 308 within the housing 301. The chassis 308 maybe sealed against the interior of the housing 301 using o-rings 308A orsimilar sealing device. The chassis 308, as explained above may beformed to define one or more chambers (not shown in FIG. 8) between itsexterior and the interior wall of the housing 301, such that whensealingly engaged to the interior of the housing 301, such chamber(s)(not shown) provide sealed, atmospheric pressure enclosures for thevarious electronic and/or electro-optical devices (not shown) disposedin the chassis 308.

Referring to FIG. 9, a bulkhead-type or pressure sealing feedthroughconnector 352 is mounted in a suitable opening in the longitudinal endof the chassis 308 that is to be in contact with the shoulder 350. Thebulkhead connector 352 mates with a corresponding bulkhead connector 354mounted in a connector ring 357. The connector ring 357 and connector354 are initially installed and electrically connected (e.g., with wiresand/or optical fibers) to the wired drill pipe communication connector(not shown) in the groove 302C of the pin through a gun drilled hole358. The gun drilled hole 358 extending into the groove 302C isconventional construction for wired drill pipe and may be configured,for example, as described in the Madhavan et al. publication referencedabove. The ring/connector assembly locks into place, for example, byusing an o-ring 356 that is disposed in both a groove in the connectorring 357 and a mating groove in the housing 301. The bulkhead connector354 and connector ring assembly 357 remains in the housing 301 afterinstallation even if the chassis 308 is removed. While the lock pin inthe chassis (see 340 in FIG. 8) helps to align the chassis 308 with thering/connector assembly 357, an additional alignment pin 356 may be usedbetween the chassis 308 and ring/connector assembly 357 to ensure properalignment of the connectors 352, 354 during assembly.

Although, male/female “stab” type connectors are illustrated for use inthe removable shoulder assembly (e.g., 318, 316 in FIG. 8) and at thebottom of the chassis as the interface with the connector ring makingelectrical contact with the wired drill pipe communication sensor in thepin connection (e.g., 325, 354 in FIG. 9) radial or ring type connectorscould be utilized here as well to remove the requirement for angularalignment between the associated mechanical parts. An example of thistype of connector assembly will be explained below with reference toFIG. 15.

Another example of a repeater does not require precise location of thesecondary shoulder face on the carrier to the outer/primary sealing faceof the box connection on the housing. Referring to FIG. 10, such exampleprovides the carrier 323 of the previous example split into two pieceswith an extremely stiff spring element 323A. The pin nose of the matingpipe segment (e.g., 202 in FIG. 2) will push against the carriersecondary sealing face, thus compressing the spring element 323A. Oncethe threaded connection is assembled, the preload of the very stiffspring element 323A will generate a similar axial force on the secondarysealing faces as would be obtained from threading a conventional pipeconnection (e.g., FIG. 2) together. Shims may be used to obtain aparticular compression range. A compression range is desirable tocontrol the amount of preload on the thread shoulders after threadingthe connection together. The shims could also be used to adjust forvariations in the housing length due to rethreading. The rest of theremovable secondary shoulder assembly and chassis assembly can beessentially as described above with reference to FIGS. 3 through 7.

A different example design of the repeater assembly will now beexplained with reference to FIG. 11. The example repeater shown at 23Ain FIG. 11 uses a housing 301 having a female threaded connection (box)at each longitudinal end and a chassis 308 assembled inside the housingfrom two discrete sections. The two chassis sections (FIG. 12) may eachbe inserted into the housing 301 from a respective longitudinal end ofthe housing 301. Each longitudinal end of the housing 301 may have asingle shoulder box connection 304 to mate with a pin end of acorresponding “pony sub” 360. Each pony sub 360 includes on onelongitudinal end thereof a double shoulder pin end configuredsubstantially as shown in and as explained with reference to FIG. 2. Thedouble shoulder connection end of each pony sub 360 is configured tomate with an adjacent pipe segment in the drill string (20 in FIG. 1).Each pony sub includes on such longitudinal end a groove for receiving acommunication coupling, also as explained with reference to FIG. 2.

The other longitudinal end of each pony sub 360 may include a doubleshoulder pin (male) threaded connection configured to engage the boxconnection at the corresponding end of the housing 301. When engagedinto the housing 301, the end of the pin compresses and traps therespective end of the chassis section against an internal shoulderformed into the interior wall of the housing 301. The foregoingstructure can be used at both longitudinal ends of the housing 301 tolock the respective chassis sections in place inside the housing 301,and to transfer at least axial loading from the inner shoulder on eachpony sub pin to the housing 301. Thus, in the present example the ponysubs 360 perform the function of the stress coupling described above.There can be a slip joint between the chassis sections where theyoverlap to sealingly, slidably engage each other. The example shown inFIG. 11 includes a pin connection on the end of each pony sub 360 thatcouples to the repeater assembly. The pony subs 360 may include either adouble shoulder box connection or a double shoulder pin connection onthe end that couples to the drill string (20 in FIG. 1).

The example shown in FIG. 11 is shown in additional detail in FIG. 12.The chassis 308 is shown as being assembled from an “upper” chassissection 308A and a lower chassis section 308B coupled to each otherinside the housing by a sealing slip joint 308E. Recesses in theexterior surface of the chassis 308 may include provisions for batteries308D and electronic circuit assemblies or boards 308C. Electrical and/oroptical connections between components in the upper chassis section 308Aand the lower chassis section 308B may be made using a radial connectorassembly 402. Each chassis section 308A, 308B may be held in placerotationally by a respective alignment pin 340A, 340B substantially asexplained above with reference to FIG. 8.

In the present example, the second shoulder for the pipe threadedconnection is provided by part of the chassis 308. Referring to FIG. 13,a wired drill pipe communication coupling (not shown) may be mounted ina groove 308F formed in the end of each electronics chassis section,e.g., 308A in FIG. 13. The present example includes an internal shoulder301B formed into the interior wall of the housing 301 to transfer axialload from the inner shoulder of the mating pipe pin connection (e.g.,pony sub 360 in FIG. 11). The axial load is transmitted through thelongitudinal end of the chassis section (e.g., 308A) to the internalshoulder 301B. The arrangement shown in FIG. 13 also serves to lock andhold each of the chassis sections (308A, 308B in FIG. 12) in placelongitudinally within the housing 301. The shoulder 301B is possible inthe present example by making the outer diameter of the housing 301larger than that used in a corresponding size drill string component.The female thread connection at each end of the housing 301 is thusdifferent than that used on the standard drill pipes and collars.Therefore, the pony collars 360 may include a pin thread to mate withthe larger, non-standard size female thread in each end of the housing301, but the opposite end of each pony sub 360 may have a standard sizedouble shoulder thread for the size drill pipe or drill collars used inthe drill string (20 in FIG. 1). In other examples, it is possible toprovide some radial wall thickness for the shoulder 301B by reducing thetaper of the housing thread (that mates to the pony sub 360) or usingthread having no taper (straight thread). Using reduced taper thread orstraight thread does not require an increase of the external diameter ofthe housing 301. The use of pony subs on each end of the housing asshown in FIG. 11 enables the use of any selected type of thread to jointhe pony subs to the housing, with the standard double shoulder threadon the opposite end of each pony sub enables the repeater to couple withany of the other sections of the pipe string.

The housing 301 may be a short sub with a length range of 3-20 feet (1-6meters) and the pony subs 360 on each end of the housing 301 may have alength selected so that the overall length of the repeater 23A is about30 feet (10 meters), which is a standard length for pipe segments.Having a repeater that is the same length as standard pipe segments maymake handling on the drilling rig easier.

Two keyways may be machined through the shoulders 301B in the housing.Keys (308E in FIG. 14) located on the chassis sections (308A, 308B inFIG. 12) may engage these keyways during insertion of the chassissections so that the chassis sections can resist torque during mating ofthe pony collars (360 in FIG. 12) to the housing 301. There may be oneor two bulkhead connectors 406 mounted in a cavity near the longitudinalend of each chassis section. Conductors from the connectors 406 extendto appropriate terminals on electronics circuit boards (not shownseparately) mounted on the chassis section. Rubber booted connectors 404that mate with the bulkhead connectors 406 can be wired to the wireddrill pipe communication coupling mounted in the groove 308F of thesecond shoulder formed in the chassis end. The rubber booted connector404 and bulkhead connector 406 when mated form a sealed connectorassembly that can be exposed to high pressure fluid without electricalor optical loss, and prevents entry of fluid into the interior of thechassis. The shoulder end of the chassis may include o-rings 301C orsimilar device to seal the chassis inside the housing 301. The featuresdescribed herein may be substantially the same for both ends of therepeater.

Referring to FIG. 15, o-rings or similar seals 410 are located in theslip joint 408 seal the chassis as assembled from pressurized fluid inthe mod flow passage in the chassis from entering the one or more sealedchambers defined by the chassis. A radial/ring conductor electrical oroptical connector, shown at 412 and 416 may be provided at the slipjoint 408 to connect conductors in both sections of the chassistogether. Contact surfaces 414 may have sufficient longitudinaldimension to allow some relative movement between the two chassissections due to thermal and pressure effects. The radial contactconfiguration can eliminate the requirement to have precise rotational(angular) alignment between each chassis section. However, the twochassis sections could use an alignment feature at the slip joint 408 ifdesired to rotationally align the two chassis sections, allowing the useof “stab” type connectors, e.g. the connectors shown at 352 and 354 inFIG. 9. The connectors on one side of the slip joint 408 are preferablyspring loaded to keep the connector sets mated notwithstanding changesin length. As in previous examples explained above, electronic and/orelectro-optical circuit boards may be mounted into pockets formed intothe exterior surface of the chassis.

Assembly of the pony subs (360 in FIG. 11) to each end of the housingmay be performed under controlled conditions to minimize the potentialfor damage to box connections on the housing (301 in FIG. 11). In theevent that there is damage to the box thread or shoulder in the housing,it is possible to rework the box or shoulder areas. As the distance fromthe box face to the shoulder is precisely selected, during rework thebox end and shoulder must be correspondingly reworked to maintain thedistance. There is provision in the present example for rework length ineach end of the housing. To maintain the proper relationship between thetwo radial/ring connector sections, there are a series of shims 418disposed on one side of the connector 412 which enables properpositioning after rework.

In the event that the chassis face is damaged, or the wired drill pipecommunication coupling has to be changed, some extra length may be addedto each end of the chassis section to allow for re-machining. Theshorter distance of the chassis end face to the small shoulder wouldrequire either that the box thread connection be reworked to shorten thedistance of the box face to the small shoulder by the same amount orshims will have to be added between the chassis shoulder and theintegral shoulder in the housing 301 to account for the re-work length.

A readout port connector (ROP) can be added for connection to theelectronic circuits (not shown) disposed on the chassis and forre-charging the batteries (308D in FIG. 12). If a ROP is not used, it ispossible to omit the alignment pin and keys between the chassis and thehousing. Omitting alignment pins and keys would allow each chassissection to rotate during make-up of the short pony pipes with therepeater sub. Rotation is permissible if the radial connector is used atthe slip joint as shown in FIG. 15.

A repeater for wired drill pipe made according to the conceptsexemplified herein may have increased torque and axial load handlingcapacity as compared to repeaters known in the art prior to the presentinvention.

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

What is claimed is:
 1. An electronic device for coupling within a wired pipe string, comprising: a housing having a threaded connection at each end configured to couple to a wired drill pipe having double shoulder threaded connections; a chassis disposed inside the housing and configured to define at least one sealed atmospheric chamber between the chassis and the housing, the chassis defining an internal passage therethrough; and at least one stress coupling configured to transmit at least one of axial loading and torque loading from both an inner and an outer shoulder of adjacent wired drill pipe segments through the housing.
 2. The device of claim 1 wherein the at least one stress coupling includes a feature on an inner thread shoulder for retaining a communication coupling.
 3. The device of claim 1 wherein a first longitudinal end of the housing includes a double shoulder threaded connection formed therein, the housing defines an internal bore from a second longitudinal end thereof having larger diameter than a diameter of an inner shoulder of the connection on the first longitudinal end, and wherein the stress coupling comprises a removable inner shoulder assembly disposed in the second longitudinal end, the removable inner shoulder assembly configured to mate to an inner shoulder of an adjacent pipe segment having a double shoulder threaded connection.
 4. The device of claim 3 wherein the removable inner shoulder assembly includes a feature in a shoulder face thereof for retaining a communication coupling.
 5. The device of claim 3 wherein the removable inner shoulder assembly includes splines to transmit torque from an inner shoulder of the adjacent pipe segment to the housing.
 6. The device of claim 3 further comprising shims between a thrust surface of the inner shoulder assembly and a corresponding thrust surface inside the housing, the shims having thickness selected to longitudinally align a face of the inner shoulder assembly with a mating inner shoulder of an adjacent double shoulder threaded connection.
 7. The device of claim 3 wherein the removable inner shoulder assembly includes circumferential grooves to transmit axial force from an inner shoulder of the adjacent pipe segment to the housing.
 8. The device of claim 3 wherein the removable inner shoulder assembly includes a spring disposed between a surface thereof configured to mate with the inner shoulder of the adjacent pipe segment and the housing, the spring having force selected so that an axial load applied to the housing by the spring is substantially the same as an axial load applied by the inner shoulder of the adjacent pipe segment to the removable inner shoulder assembly.
 9. The device of claim 1 wherein the housing defines an internal shoulder to limit axial movement therethrough of the chassis.
 10. The device of claim 1 wherein the internal bore defined by the chassis has a diameter at least as large as a smallest internal diameter of any part of a double shoulder connection pipe string coupled thereto.
 11. The device of claim 1 further comprising a jam nut disposed inside the housing and configured to retain the chassis inside the housing.
 12. The device of claim 11 further comprising a biasing device disposed between a longitudinal end of the chassis and the jam nut.
 13. The device of claim 1 wherein the housing defines an internal bore having a shoulder proximate each longitudinal end, wherein the chassis defines two chassis sections each insertable into the housing through one longitudinal end, wherein the chassis sections each define an external diameter feature configured to engage a respective shoulder in the internal bore in the housing, wherein the chassis sections sealingly, slidably engage each other within the internal bore, and wherein the stress coupling comprises a pony sub configured to threadedly engage both an inner shoulder and an outer shoulder of a double shoulder threaded connection at one longitudinal end, the stress coupling configured to threadedly engage the housing at the other longitudinal end and to axially compress the chassis section engaged on the respective internal shoulder in the housing.
 14. The device of claim 13 wherein each pony sub comprises a groove for retaining a communication coupling in an inner shoulder thereof of the end configured to engage the double shoulder threaded connection.
 15. The device of claim 13 wherein at least one of electrical and optical coupling is made between the two chassis sections using a radial connector.
 16. The device of claim 13 wherein the internal bore defined by the chassis has a diameter at least as large as a smallest internal diameter of any part of a double shoulder connection pipe string coupled thereto.
 17. An electronic device for coupling within a wired pipe string, comprising: a housing having a threaded connection at each end configured to couple to a wired drill pipe having double shoulder threaded connections; means for sealingly enclosing at least one electronic component disposed within the housing, the means for enclosing defining a sealed internal passage therethrough; and means for transmitting at least one of axial loading and torque loading from both an inner and an outer shoulder of adjacent wired drill pipe segments through the housing.
 18. A method for assembling an electronic device for coupling within a wired pipe string, comprising: inserting a chassis into a housing having a threaded connection at each end configured to couple to a wired drill pipe having double shoulder threaded connections, the chassis configured to define at least one sealed atmospheric chamber between the chassis and the housing, the chassis defining an internal passage therethrough; assembling at least one stress coupling to one end of the housing, the stress coupling configured to transmit at least one of axial stress and torque loading from both an inner and an outer shoulder of adjacent wired drill pipe segments through the housing, the assembling including making at least one of electrical and optical connection between a contact disposed in the chassis and a connector disposed in the at least one stress coupling.
 19. The method of claim 18 wherein: the inserting the chassis includes inserting each of two chassis sections into the housing through one longitudinal end, wherein the chassis sections each define an external diameter feature configured to engage a respective shoulder in the internal bore in the housing, wherein the chassis sections sealingly, slidably engage each other within the internal bore, and wherein the assembling the at least one stress coupling comprises threadedly engaging a pony sub configured to engage both an inner shoulder and an outer shoulder of a double shoulder threaded connection at one longitudinal end, the pony sub configured to threadedly engage the housing at the other longitudinal end and to axially compress the chassis section engaged on the respective internal shoulder in the housing.
 20. The method of 18 wherein the inserting the chassis includes sliding the chassis into the housing from one longitudinal end thereof, a first longitudinal end of the housing including a double shoulder threaded connection formed therein, the housing defining an internal bore from a second longitudinal end thereof having larger diameter than a diameter of an inner shoulder of the connection on the first longitudinal end, and wherein the assembling the stress coupling comprises inserting a removable inner shoulder assembly into the second longitudinal end, the removable inner shoulder assembly configured to mate to an inner shoulder of an adjacent pipe segment having a double shoulder threaded connection.
 21. The method of claim 18 further comprising threadedly engaging at least one longitudinal end of the housing to a segment of wired drill pipe having double shoulder threaded connections thereon, the threadedly engaging comprising making contact between an outer shoulder of the housing and a corresponding shoulder of the segment, the threadedly engaging comprising making contact between an inner shoulder of the segment and the at least one stress coupling 